FIG. 1 shows an assembly of shifter dog wherein stick 1 is used to shift gears and has either a spherical end 2 as shown or an end with an alternate geometry which lodges itself on the slot 3 of the shifter dog. On lodging, the shifter dog transmits the force applied by the driver on the stick 1 to a shaft 4 or an appropriate mechanical device which is specific to the design of the gear box to enable changing of the gear which is engaged to the drive shaft. FIG. 2 shows a typical shifter dog as in prior art, where the entire shifter dog is produced out of a homogenous ferrous material either by forging, casting or any other alternate manufacturing processes. In the FIG. 2, slot 3 where the spherical end of stick 1 engages requires sufficient mechanical strength and wear resistance to withstand the loads imparted by the driver intending to shift the gears. To impart sufficient strength and wear resistance, the portion in the shifter dog is usually induction hardened or the shifter dog as a whole is through hardened. The cylindrical portion 6 as shown in FIG. 2 is the portion at which the shaft is affixed to the shifter dog, through which necessary force required to the shift gears is transmitted. Thus, the homogenous shifter dog undergoes multiple machining and multiple heat treatments to get to the final shape and strength respectively. On the other hand, due to uniform material composition of the shifter dog and repeated contact between slot 3 and the spherical end of stick 1, the wear resistance and load withstanding capacity or higher strength in the shifter dog is considerably reduced.
In view of aforementioned limitations, there is a need to develop a shifter dog which is capable of having higher strength than that of the existing shifter dog. Also, there is a need to introduce distinct material compositions at locations in the shifter dog which are repeatedly used or contacted by the ball end of the stick. In addition, there is also a need to provide a method of manufacturing a method to optimise material composition used in the shifter dog.